Apparently when you have a heart attack your cells don't die of oxygen starvation in 5 minutes, they die hours later, but if you get restarted after 5 minutes the infusion of oxygen causes your cells to commit suicide because they think they've become abnormal. Major repercussions in resuscitation theory. Wiggy. Link to Newsweek article.

Nah, I mean, some people will always say that about any medicine, but I think the usual reaction to stuff like this is to redefine death. I think the definition of death is "they can't bring you back". So, if you can be revived, then by definition, you weren't dead, just "near dead". Which of course is the whole "near death experience", where you are in a state that would be defined as dead, but only if it were to persist indefinitely... or something.